The present invention relates to a control system for a jet ventilator.
Jet ventilators, and in particular high frequency jet ventilators, operate by introducing into the airway of a patient a relatively small volume of gas on the order of 100 milliliters at a high velocity by way of a short pulse of, for example, 130 milliseconds. This high speed stream will entrain and accelerate a larger volume of stationary gas through the airway. The pulse duty cycle of typically 33 percent on and 66 percent off is repeated up to several hundred times per minute, resulting in adequate ventilation to the patient's lungs.
In conventional high speed jet ventilators, the control therefore is asynchronous with respect to the cardiac rate of the patient and moreover is merely coarsely adjustable with respect to the duty cycle of the ventilation pulse.